1. Field of the Invention
The present invention relates to a disk drive, and more particularly, to a disk drive having a heat sink device to dissipate heat generated from semiconductor chips of a printed circuit board to the outside.
2. Description of the Related Art
Hard disk drives (HDDs), which are data storage devices used for computers, use read/write heads to reproduce or record data with respect to a disk. In the HDD, the read/write head performs its functions while being moved by an actuator to a desired position while lifted to a specified height from a recording surface of a rotating disk.
FIG. 1 is an exploded perspective view illustrating the configuration of a conventional hard disk drive. FIG. 2 is a side view illustrating the hard disk drive of FIG. 1.
Referring to FIGS. 1 and 2, a conventional hard disk drive includes a base member 11 and a cover plate 12. A spindle motor 30 to rotate a disk 20 and an actuator 40 to move a read/write head for recording and reproducing data to a desired position on the disk 20 are installed on the base member 11. The cover plate 12 is coupled to the base member 11 to protect the disk 20 and the actuator 40 by encompassing the same.
The actuator 40 includes a swing arm 42 rotatably coupled to a pivot bearing 41 installed on the base member 11, a suspension 43 installed at one end portion of the swing arm 42 and supporting a slider having the head mounted thereon toward a surface of the disk 20 to be elastically biased, and a voice coil motor (VCM) 45 to rotate the swing arm 42. The voice coil motor 45 is controlled by a servo control system to rotate the swing arm 42 in a direction following the Fleming's left hand rule by the interaction between current applied to the VCM coil and a magnetic field formed by a magnet. That is, when the power of the hard disk drive is turned on and the disk 20 starts to rotate, the voice coil motor 45 rotates the swing arm 42 counterclockwise to move the head toward a position above a recording surface of the disk 20. When the power of the hard disk drive is turned off and the disk 20 stops rotation, the voice coil motor 45 rotates the swing arm 42 clockwise so that the head is moved to a position not above the disk 20.
A printed circuit board 50 is installed on a rear surface of the base member 11. A plurality of semiconductor integrated circuit chips 52 to drive a disk drive is mounted on the printed circuit board 50. Although not shown in the drawing, a plurality of circuit devices, and wirings to electrically connect the semiconductor chips 52 and the circuit devices, are arranged on the printed circuit board 50.
A thin insulation panel 60 for insulation between the semiconductor chips 52, the circuit devices, and wirings, which are provided on the printed circuit board 50, and the base member 11, is arranged between the base member 11 and the printed circuit board 50. The insulation panel 60 is made of a material exhibiting an electric insulation feature, a thermal insulation feature, and a buffering feature so that it also has functions of insulating heat, reducing noise, and absorbing shocks and vibrations. That is, the insulation panel 60 blocks transfer of heat generated from the semiconductor chips 52 of the printed circuit board 50 into the disk drive via the base member 11.
Since the height of hard disk drives used for desktop computers is loosely restricted, the semiconductor chips can be mounted on a rear surface of the printed circuit board, that is, facing toward the outside. Thus, in this case, since the semiconductor chips are directly exposed to the outside air, the heat generated from the semiconductor chips can be easily dissipated.
However, in hard disk drives used for portable computers, for example, notebook computers, since the height thereof is tightly restricted, as shown in FIGS. 1 and 2, the semiconductor chips 52 can be mounted on an upper surface of the printed circuit board 50, that is, a surface toward the base member 11. Accordingly, the heat generated from the semiconductor chips 52 is not easily dissipated to the outside and remains between the printed circuit board 50 and the base member 11 for a long time. Although the insulation panel 60 has an insulation function, it does not dissipate the heat to the outside. As a result, after a long time of use, the heat generated from the semiconductor chips 52 is transferred to the base member 11. Accordingly, the temperature of the head, the spindle motor 30, and the actuator 40 increases so that performance of the disk drive deteriorates. Also, since the thermal conductivity coefficient of the insulation panel 60 is quite low, the heat generated from the semiconductor chips 52 cannot be distributed uniformly throughout the entire surface of the insulation panel 60. Thus, a rise in the temperature of the base member 11 at a portion near the semiconductor chips 52 generating a large amount of heat is relatively great. As the rise in the temperature differs according to the portions of the base member 11, the base member 11 is deformed so that the entire configuration of the disk drive is deformed and thus performance thereof may be deteriorated.
FIG. 3 shows that there is a considerable difference in the amount of deformation according to the portions of the base member due to the local temperature rise in the base member by the heat generated from the semiconductor chips in the conventional hard disk drive shown in FIG. 1.